A data storage device, in particular a data storage device using a non-volatile storage medium, includes a plurality of blocks. Each block includes a plurality of pages, each page is for storing data with at least one storage unit, and the storage unit may be 512 B (byte) or preferably 4 KB. Blocks are also divided into empty blocks (or spare blocks) and non-empty blocks (or in-use blocks) depending on whether data is stored therein or not. For data management and access, the data storage device needs to establish and store a host-to-flash physical address mapping table (H2F table), which is simply referred to as a mapping table in the present invention. When the data storage device is in operation, the mapping table is copied to a dynamic random access memory (DRAM) to increase the efficiency of data management and access. In addition, depending on the size of recorded content, in general the size of a mapping table is 1/1000 of the data storage capacity of a data storage device. For example, if the size of a data storage device was 256 GB (gigabyte), the size of the corresponding mapping table would be 256 MB (megabyte) for storing a complete mapping table and system data, parameters or programs required for operation of the data storage device.
For a data storage device that is only provided with a small-sized DRAM or static random access memory (SRAM) (i.e., the DRAM or SRAM is not large enough to store an entire mapping table), there is a technical need for efficiently using the provided small-sized DRAM or SRAM for data management and access.